The introduction of light-emitting diodes (LED) has ushered in a new era for light-emitting devices. LED lights, thanks to their advantages of small size, long life-time, low power consumption and low heat dissipation, have replaced incandescent lamps in many wearable light-emitting devices. Furthermore, LEDs provide more operating modes over chemiluminescence substrates (used in glow sticks) which are short-term light-sources and can be used only once.
A variety of wearable light-emitting devices used for safety warnings, cheering at sporting or concert events, or light show performance currently exist. These devices can be classified into two groups:                Group 1: wearable light-emitting devices that are controlled by a remote control center.        Group 2: wearable light-emitting devices that are controlled by the wearer.        
Wearable light-emitting devices of group 1 are usually used in events with a large audience such as sports competitions or music concerts. Each device typically comprises a power supply unit (battery), a control unit, a signal transmitter/receiver, and a few LED lights. They are usually introduced in the form of light-emitting bracelets that are worn on the wrist. These bracelets are wirelessly driven by a remote control center via radio (Xyloband, Ripple-light) or infrared (PixMob, SLC). The advantage of these devices is that they allow creating beautiful lighting effects at the macro level. However, the possible control of the wearer on these devices is limited to turning on and turning off the device, not the control of light and color effects. Moreover, the use of these devices always requires a control center. This makes operating such devices more complex. The mobility of wearers is restrained within the coverage of the control center.
Wearable light-emitting devices of group 2 are usually used by individuals for the purpose of safety warnings or light show performance. Each device typically comprises a power supply unit (battery), a control unit, a push button, and a few LED lights. They can be introduced in the form of light-emitting bracelets (sub-group 2a), glowing gloves (sub-group 2b), or small light-emitting devices that will be worn on the fingertips (sub-group 2c). For devices of sub-groups 2a and 2b, the push button allows to switch between pre-programmed modes: light off, blinking light, solid light. The advantage of these devices is their simple control: pressing a button. Their inconvenience, however, is that they usually require the wearer to use her/his non-wearing hand to manipulate the button. For example, the invention of Kiser (U.S. Pat. No. 8,477,986 on Jul. 2, 2013) does not allow the wearer control the device using the wearing hand. To overcome this drawback, Zackess glove (U.S. Pat. No. 9,013,281 on Apr. 21, 2015) is designed with a switch mechanism where a first contact assembly locates on a thumb and a second contact assembly locates on an index finger of the glove. This allows the wearer to control the device by simply moving the thumb of her/his wearing hand. However, this device only allows the user to turn on and off the blinking light with a predefined frequency. It is impossible to manipulate the light and color effects.
For devices in sub-group 2c (for example, Emazinglights of Brian Lim and Montes de Oca and Ramiro, US Patent Application Publication No. 2014/0265906 on Sep. 18, 2014; light-emitting devices of Futuristiclights), the wearer can use the wearing hand to press the on-device-button to switch between pre-programmed display modes because the devices are worn on the fingertips. These devices have however a few drawbacks. First, because the devices must be worn on the fingertips, the wearer should always use gloves to keep these devices in position. This makes it difficult to hold other objects or perform other grasping tasks while using these devices. The second drawback of these devices is not allowing the wearer to control the on/off time of the LED beyond the preprogrammed modes. Some devices in this sub-group have integrated motion sensors enabling automatic change of display modes when the wearer varies her/his hand moving speed. For example, an accelerometer sensor allows the LED to turn on when there is motion and the LED to turn off when there is no motion. This enables users to fully control the on/off time of the LED. However, the downside of this solution is that it does not allow the wearer to turn on/off the LED independently with the movement of the device.
The device which is considered to be the closest to this invention is “LED 3D printing wristbands with accelerometer sensor” by Caleb Kraft (3D-Printed RGB LED Bracelet Uses Accelerometer (called “3D-printing LEDs bracelet”). The device includes a power supply unit (battery), a micro-controller, an accelerometer sensor and a few LED lights. The bracelet allows the wearer to interact with it with shaking motions of the hand. When no motion detected, the color of the LEDs will gradually change following a predetermined color sequence. When there are shaking motions in a short time, the LEDs will skip a few colors in the sequence. The advantage of this device is that it allows the wearer to interact with the bracelet by simple actions such as a shaking motion. However, like many devices mentioned above, this bracelet does not allow the wearer to control the on/off time of the LEDs. In addition, because the interaction between the wearer and 3D-printing LEDs bracelet is shaking, any fast motion in any direction with a sufficient intensity can lead to a result that the LEDs will skip a few colors. That means there will be no difference among shaking motions in left, right, up or down directions. Another drawback of 3D-printing LEDs bracelet is not allowing the wearer to move her/his hand with the desired speed while maintaining a display program.
This context makes necessary introducing a wearable light-emitting device and a control method that can overcome the disadvantages of the devices mentioned above.